Transfer iron



Feb. 27; 1951 T. MARSTON El AL 2,543,035

TRANSFER IRON Filed April 27, 1946 10 ll l l l l 12 Z I i- I "e INVENTORS Ham/ nga flars/wz Wmi/zmfl J? lax rm ATTORNEY Patented Feb. 27, 1951 Lawrence, Wilmington,

Del., assignors to Kaumagraph Company, a corporation of Delaware Application April 27, 1946, Serial No. 665,597

1 '1 Claim.

The present invention relates to an improved transfer iron for applying heat transfers.

Heat transfers are in wide use for the marking of various materials, particularly for applying markings to articles formed from textile materials such as hosiery and other wearing apparel. The transfers employed for this purpose comprise a suitable backing strip or base, usually made of paper, bearing on one face a marking composition in the shape of the design or printing to be applied to the article. The article is marked by placing the transfer on it with the marking composition in contact with the surface to be printed and then applying heat and. pressure to the back of the transfer base. Under the influence of the heat and pressure the marking composition is transferred to the surface of the article, on which it remains when the is stripped away. In applying such transfers on a commercial scale, for example, in a garment factory, it is a common practice to apply the heat and pressure to effect transfer of the design. or printing by means of a specially designed tool. known as a transfer iron. These irons are commonly designed to be manipulated by the operator by hand to apply the transfers individually.

While this method of applying the transfers is generally saisfaotory, it has certain drawbacks and disadvantages. For example, when the transfers are employed in marking hosiery and other fabrics formed of silk and various thermo plastic synthetic fibers that have a tendency to soften at or adjacent the temperatures employed in transfer marking operations, the iron sor'netimes produces a glazed effect on the fabric adjacent transfer marking. In the application of a transfer marking, it is important that the ink either penetrate the surface and be absorbed by it, in which case a of good appearance is usually obtained, or that the application of the transfer be made in such a way as not to squeeze the ink out and cause it to smear. Squeezing and smearing of the ink is particularly apt to occur when the application is made to a non-absorbentsurface or a hard surface. With this type of surface the skill of the operator is a determining factor in the production of markings of good quality. A clumsy operator will produce a smear when a skillful operator with the same transfer and the same surface would not. When. the surface is hard and non-absorbent, as is the case, for example, when the markings are to be applied to Bakelite panels, the application must be made very deftly if a clear impre is to be obtained. Heat transfers of the type referred to have not proved successful heret of hard surfaces which are sligl y If the surface to which the transfer is to be applied is not plane, the application of pressure by the unyielding surface of the shoe of the transfer iron results in the application of varying degrees fore for the marking of pressure at various parts of the transfer with the result that too great pressure is applied at the high points and insufficient pressure at the low points. The resulting markings show great irregularity. For this reason it has not been possible heretofore to employ heat transfers for the marking of grained wood surfaces with any substantial measure of success.

It is an object of the present invention to provide a transfer iron which will be effective in applying heat transfers to hard and non-absorbent surfaces to produce markings free from smearing.

A further object of the invention is to provide a heat transfer iron with which heat transfers maybe applied with uniformly good results, largely independent of the skill of the operator.

A further object of the invention is to provide a heat transfer iron which will be effective for the application of transfers to materials having a slightly uneven hard surface.

A further objectis to provide a heat transfer iron which may be employed to apply transfer markings to textile materials without producing a polished or glazed surface on the textile material adjacent the marking.

Other objects and advantages of the invention will appear more fully from the following detailed description and accompanying drawing in which Fig. 1 is a View in elevation, partly broken away, of a hand transfer iron embodying the invention, and Fig. 2 is a plan View, looking upwardly, of the iron of Fig. 1.

In accordance with the invention we have found that a transfer iron which is free from the disadvantages described above may be formed by providing the iron with a heat transfer shoe having a working surface which is sufficiently soft so that it may be locally compressed during the transfer operation, to conform to any irregu'larities in the surface of the article being marked, which is sufiiciently resilient to return promptly to its original fiat shape after such deformation, which is characterized by adequate heat conductivity, and which is capable of retaining its softness and resiliency, without vulcanization or other permanent change for extended periods at temperatures in the neighborhood of 400 to 509 F.

Referring to the accompanying drawing, the transfer iron selected for purposes of illustration is of the hand tool type suitable for use by an operator to apply the transfers one at a time to individual articles to be marked. The transfer iron comprises a hand grip or handle i which is contoured as shown to be comfortably grasped by the hand. Supported on the handle at its lower end is a casing 2 in which is enclosed a suitable electrical resistance heating element (not shown). Below the heating element and supported on the casing 2 is the improved shoe element of the present invention. As shown it consists of a metallic plate 3 carrying on its lower face a resilient pad 5 conforming in outline to the plate and provided with a lower exposed working face 6. Desirably, the working face 6 is smooth and substantially plane. The pad 5 may be secured to the plate 3 in any suitable fashion. Preferably the pad is permanently adhered or welded to the plate by an adhesive of a nature capable of forming a strong bond between the metal of the plate and the resilient material from which the pad' 5 is formed and of maintaining such bond under the temperatures maintained in operating the iron.

The shank 8 connecting the housing 2 to the handle I is provided with a group of radiating fins 9 for the purpose of causing heat to be rapidly dissipated from the shank 8 to prevent overheating of the handle I and to protect the hand of the operator.

The upper end of the handle is provided with a jack l2 for the reception in a conventional manner of a plug 10 connected through the cord II to a source of electrical energy at an appropriate voltage. Electrical connections (not shown) extend through the handle i from the jack !2 to the resistance heating element which is contained within the housing 2.

The pad 5 is formed from a material which is sufficiently soft to yield locally when the iron is pressed against a transfer to conform to irregularities in the surface of the backing strip of the transfer which are brought about by irregularities or unevenness in the surface of the article which is being marked. At the same time, the pad should be sufliciently resilient to insure that the working surface 5 will return immediately to its original plane condition when the iron is lifted from the work. The material from which the pad 5 is formed must also have enough heat conductivity to insure that heat supplied from the plate 3 will be transmitted through the pad at a sufficient rate to maintain a temperature at the working face 6 in the neighborhood of 400 to 500 F. -t is also desirable that this material be such that it is capable of retaining its softness and resiliency for extended periods at the temperatures to which it is exposed in the operation of the iron.

The thickness of the pad may vary considerably depending upon the physical characteristics of the material from which it is formed. Generally a thickness between h" and 1%, will be found to give good results.

As an illustration of one material suitable for forming the pad 5, we have found that silicone rubber is highly satisfactory. A silicone rubber having a durometer hardness of about 30 is particularly satisfactory for this purpose when the pad is made approximately one-eighth of an inch thick.

The operation of the improved heat transfer iron will be largely apparent from the foregoing description. The transfer to be appliedis placed on the article to be marked with the marking composition of the transfer in contact with the article and with the transfer base exposed. The iron, having been brought to heat, is grasped by the handle I and pressed down against the transfer to apply heat and pressure to the transfer through the working face 5. As the iron comes in contact with the transfer the pad 5 will yield locally to permit the working face 6 to conform closely to the exposed surface of the base of the transfer and thus apply pressure more or less uniformly over the entire area of the trans fer. This uniform pressure distribution will occur even though the surface of the article being marked is slightly uneven as is the case, for example, with various grained wood surfaces. If the surface of the article being marked is hard and relatively non-absorbent of the marking ink, the softness of the pad 5 and the uniform pressure distribution which it produces will result in a neat impression even though the pressure applied by the operator may be somewhat more or less than the ideal pressure.

The yieldability of the pad 5 reduces the strain on the wrist of the operator as contrasted with that which is experienced when the working face of the shoe of the iron is hard and unyielding, particularly when operating on relatively unyielding material. In the course of a days operation this results in noticeably less fatigue for the operator.

In order to insure that heat will be transferred from the electrical resistance of the ironthrough the metal plate 3 and the pad 5 at a sufficiently rapid rate without the necessity of increasing the temperature inside the iron, it will usually be desirable to form the metal plate 3 from a metal characterized by relatively high heat conductivity such as aluminum or copper. Aluminum has the further advantages over the metals ordinarily used that it has a relatively low density and a high heat capacity.

Various changes in the details of the construction of the transfer iron and in the selection of the metals used in forming the several essential elements of the iron may be made without departing from the invention which is not to be deemed as limited otherwise than as indicated by the language of the appended claim.

We claim:

A hand transfer iron for applying transfer markings by heat and pressure to hard non-absorbent surfaces and to gene-rally planar surfaces of slightly uneven surface contour such as fabrics having a seam line running therethrough, comprising an upwardly extending handle for lifting said iron and for applying it to saidsurface, a housing connected to the lower end'of said handle, a shoe for the bottom of the housing comprising a rigid planar surfaced metal plate secured to the housing and a resilient, heat resistant, heat conductive pad composed of silicone rubber attached to the lower side of the plate and adapted when said iron is heated and pressed thereon to conform to slight unevenness of the contour of the surface to which the markings are to be applied, and an electric heating element disposed within said housing in heat transmitting relation to said metal plate.

TROWBRIDGE MARSTON. WIN'IHROP S. LAWRENCE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,653,901 Haessly Dec. 27, 1927 2,051,684 Dick Aug. 18, 1936 2,196,514 Alexander Apr. 9, 1940 2,219,419 Jacobus Oct. 29, 1940 OTHER REFERENCES Silicone Rubber, Rubber Age (Nov. 1944 volume 56, #2, pages 173-5. 

